Re: SELECT performance problem on a join

On Wed, 25 Apr 2001, Patrice Espié wrote:

> Hello,
>
> I have a great problem with performances of my database, on the SQL request:
> ---------------
> select t_test.doc_id,  t_test.f_num_centre, t_test.f_num_candidat from
> t_test, doc where t_test.doc_id=doc.id and doc.docsubset_id=2000077392
> ---------------
> The doc table has 36.000 rows, and t_test the same. There is an index on doc
> (docsubset_id) and an index on t_test (doc_id). There is others index too.
>
> When I send this request, I must wait for about 45 sec. before the results
> appears.
> The server is a BI-PII 266, and there is about no activity on the database
> neither on the server.
>
> When I was using this request under MS-SQLServer (v6), the wait time was
> about nothing.
>
> What's wrong ?

A few questions:
  1) Which version of postgres are you using?
  2) Have you 'VACUUM ANALYZE t_test' and 'VACUUM ANALYZE doc' yet?

Try #2, it should help you quite a bit.

-- Dave